VENTS OKF 600x300-3

Direct-expansion duct coolers are designed for cooling of supply air in rectangular ventilation systems and can be used either for supply or supply and exhaust units.

DESIGN

The DX coolers are available in OKF and OKF1 mofications. The OKF1 cooler has a simplified design. The cooler casing is made of galvanized sheet steel, the piping is made of copper tubes and the heat exhange surface is made of aluminium plates. The coolers are available in 3 rows modification and designed for operation with R123, R134а, R152а, R404а, R407с, R410а, R507, R12, R22 cooling agents. It is equipped with a droplet separator and a drain pan for condensate collection and removal.

For OKF and OKF1 models by default the service side is located on the right side from the air stream direction.

The OKF cooler service side location can be changed by coil turning by 180°. The OKF1 modification does not have this option.

MOUNTING

Mounting is effected by means of flange connection. Direct-expansion cooling coils, can be installed horizontally only to enable the condensate draining.

Installation shall be performed in such a way as to provide the uniform air srteam distribution along the entire cross section.

The air filter shall be installed at the cooler inlet to ensure the cooler protection against dirt and dusting.

The cooler can be installed at the fan inlet or outlet. If the cooler is located at the fan outlet the air duct between the cooler and the fan shall be at least 1-1.5 m long to ensure the air stream stabilization.

To attain the maximum cooling capacity the cooler must be connected on counter-flow basis. All the nomographic charts in the catalogue are valid for such connection.

The droplet separator is made of polypropylene profile and prevents condensate dripping from the cooling tubes by the cooling air flow. While selecting a cooler type consider that the most suitable speed of the air flow for the efficient droplet separator operation is up to 4 m/s.

Condensate draining from the cooler shall be performed through the U-trap. The U-trap height depends on the total pressure in the fan. The trap height can be calculated using the figure and the table below.

H (mm)

K (mm)

P (Pa)

100

55

600

200

105

1100

260

140

1400

Н - U-trap height

К - drain height

Р - total pressure in the fan

To ensure the correct and safe cooler operation use the automation system providing the complex control and automatic regulation of the cooling capacity and air cooling temperature.

Air Speed. Starting from 2500 m3/h on the air flow scale draw a vertical line 1 till the air speed axis. It makes 3.75 m/s.

Supply air temperature. Prolong the line 1 up to the point where it crosses the outside air temperature (e.g. +30°C); then draw a horizontal line 2 from this point to the left till crossing the outside air humidity (e.g. 50%). From this point draw a vertical line 3 to the supply air temperature at cooler outlet axis on top of the graphic (+22.5°C).

Cooling coil capacity. Prolong the line 1 up to the point where it crosses the outside air temperature (e.g. +30°C) and draw a horizontal line 4 from this point to the right until it crosses the outside air humidity curve (e.g., 50%), from here draw a vertical line 5 up to the scale representing the cooling capacity (10.5 kW).

Cooling agent discharge. Prolong the line 5 down to cooling agent discharge axis at the bottom of the graphic 6 (225 kg/hour).

Cooling agent pressure drop. Draw the line 7 from the point where the line 6 crosses the black curve to the pressure drop axis. (17.0 kPa).